With increase of device density of integrated circuitry (IC), spacing between components decreases continuously. In the ICs, capacitance between conductive interconnecting components, especially interconnecting wirings, increases, causing degradation of IC performance. On the other hand, low power consumption is desirable even for devices of low performance, for which the capacitance also needs to be reduced. A method for reducing the capacitance is to form air gap between the interconnecting components, which may cause mechanical and/or electrical stability problems.
Therefore, low capacitance between the interconnecting components is desirable for the ICs.